/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsISupports.idl"

interface nsIURI;
interface nsILoadContext;
interface nsINetworkPredictorVerifier;

typedef unsigned long PredictorPredictReason;
typedef unsigned long PredictorLearnReason;

/**
 * nsINetworkPredictor - learn about pages users visit, and allow us to take
 *                       predictive actions upon future visits.
 *                       NOTE: nsINetworkPredictor should only
 *                       be used on the main thread.
 */
[scriptable, uuid(acc88e7c-3f39-42c7-ac31-6377c2c3d73e)]
interface nsINetworkPredictor : nsISupports
{
  /**
   * Prediction reasons
   *
   * PREDICT_LINK - we are being asked to take predictive action because
   * the user is hovering over a link.
   *
   * PREDICT_LOAD - we are being asked to take predictive action because
   * the user has initiated a pageload.
   *
   * PREDICT_STARTUP - we are being asked to take predictive action
   * because the browser is starting up.
   */
  const PredictorPredictReason PREDICT_LINK = 0;
  const PredictorPredictReason PREDICT_LOAD = 1;
  const PredictorPredictReason PREDICT_STARTUP = 2;

  /**
   * Start taking predictive actions
   *
   * Calling this will cause the predictor to (possibly) start
   * taking actions such as DNS prefetch and/or TCP preconnect based on
   * (1) the host name that we are given, and (2) the reason we are being
   * asked to take actions.
   *
   * @param targetURI - The URI we are being asked to take actions based on.
   * @param sourceURI - The URI that is currently loaded. This is so we can
   *   avoid doing predictive actions for link hover on an HTTPS page (for
   *   example).
   * @param reason - The reason we are being asked to take actions. Can be
   *   any of the PREDICT_* values above.
   *   In the case of PREDICT_LINK, targetURI should be the URI of the link
   *   that is being hovered over, and sourceURI should be the URI of the page
   *   on which the link appears.
   *   In the case of PREDICT_LOAD, targetURI should be the URI of the page that
   *   is being loaded and sourceURI should be null.
   *   In the case of PREDICT_STARTUP, both targetURI and sourceURI should be
   *   null.
   * @param loadContext - The nsILoadContext of the page load we are predicting
   *   about.
   * @param verifier - An nsINetworkPredictorVerifier used in testing to ensure
   *   we're predicting the way we expect to. Not necessary (or desired) for
   *   normal operation.
   */
  void predict(in nsIURI targetURI,
               in nsIURI sourceURI,
               in PredictorPredictReason reason,
               in nsILoadContext loadContext,
               in nsINetworkPredictorVerifier verifier);


  /*
   * Reasons we are learning something
   *
   * LEARN_LOAD_TOPLEVEL - we are learning about the toplevel resource of a
   *                       pageload (NOTE: this should ONLY be used by tests)
   *
   * LEARN_LOAD_SUBRESOURCE - we are learning a subresource from a pageload
   *
   * LEARN_LOAD_REDIRECT - we are learning about the re-direct of a URI
   *
   * LEARN_STARTUP - we are learning about a page loaded during startup
   */
  const PredictorLearnReason LEARN_LOAD_TOPLEVEL = 0;
  const PredictorLearnReason LEARN_LOAD_SUBRESOURCE = 1;
  const PredictorLearnReason LEARN_LOAD_REDIRECT = 2;
  const PredictorLearnReason LEARN_STARTUP = 3;

  /**
   * Add to our compendium of knowledge
   *
   * This adds to our prediction database to make things (hopefully)
   * smarter next time we predict something.
   *
   * @param targetURI - The URI that was loaded that we are keeping track of.
   * @param sourceURI - The URI that caused targetURI to be loaded (for page
   *   loads). This means the DOCUMENT URI.
   * @param reason - The reason we are learning this bit of knowledge.
   *   Reason can be any of the LEARN_* values.
   *   In the case of LEARN_LOAD_SUBRESOURCE, targetURI should be the URI of a
   *   subresource of a page, and sourceURI should be the top-level URI.
   *   In the case of LEARN_LOAD_REDIRECT, targetURI is the NEW URI of a
   *   top-level resource that was redirected to, and sourceURI is the
   *   ORIGINAL URI of said top-level resource.
   *   In the case of LEARN_STARTUP, targetURI should be the URI of a page
   *   that was loaded immediately after browser startup, and sourceURI should
   *   be null.
   * @param loadContext - The nsILoadContext for the page load that we are
   *   learning about.
   */
  void learn(in nsIURI targetURI,
             in nsIURI sourceURI,
             in PredictorLearnReason reason,
             in nsILoadContext loadContext);

  /**
   * Clear out all our learned knowledge
   *
   * This removes everything from our database so that any predictions begun
   * after this completes will start from a blank slate.
   */
  void reset();
};

%{C++
// Wrapper functions to make use of the predictor easier and less invasive
class nsIChannel;
class nsIDocument;
class nsILoadContext;
class nsILoadGroup;
class nsINetworkPredictorVerifier;

namespace mozilla {
namespace net {

nsresult PredictorPredict(nsIURI *targetURI,
                          nsIURI *sourceURI,
                          PredictorPredictReason reason,
                          nsILoadContext *loadContext,
                          nsINetworkPredictorVerifier *verifier);

nsresult PredictorLearn(nsIURI *targetURI,
                        nsIURI *sourceURI,
                        PredictorLearnReason reason,
                        nsILoadContext *loadContext);

nsresult PredictorLearn(nsIURI *targetURI,
                        nsIURI *sourceURI,
                        PredictorLearnReason reason,
                        nsILoadGroup *loadGroup);

nsresult PredictorLearn(nsIURI *targetURI,
                        nsIURI *sourceURI,
                        PredictorLearnReason reason,
                        nsIDocument *document);

nsresult PredictorLearnRedirect(nsIURI *targetURI,
                                nsIChannel *channel,
                                nsILoadContext *loadContext);

} // mozilla::net
} // mozilla
%}
